A blow mould apparatus for moulding plastic preforms into plastic containers with a first mould carrier element and a second mould carrier element which is swivelable about a connecting axis in relation to the first mould carrier element, wherein the mould carrier elements cooperate such that in a closed state of the blow mould apparatus they form in their interior a cavity in which the plastic preforms can be expanded into plastic containers, and with a locking device which locks the first mould carrier element in relation to the second mould carrier element in order to hold the blow mould apparatus at least temporarily in a closed state, wherein the locking device has at least one locking element which is arranged on a mould carrier element, is mobile and cooperates with the other mould carrier element to lock the mould carrier elements and wherein the locking device comprises a mobile actuation element, the movement of which is coupled at least temporarily with a movement of the locking element, the actuation element and/or locking element being mobile between at least two prespecified positions.